Transformer interface for preventing EMI-based current imbalances from falsely triggering ground fault interrupt
US7375940B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 28, 2005 |
| Grant date | May 20, 2008 |
| Priority date | — |
| Expiry date | Dec 28, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/337
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A transformer interface prevents a false ground fault interrupt in a power supply arrangement. The power supply arrangement has a line wire and a neutral wire connected by way of a ground fault interrupt circuit to an electrically powered device, to which a ground wire is also coupled. The interface has current imbalance sensor transformer windings coupled to the line and neutral wires. A ground wire current sensor transformer winding is coupled to the ground wire. A detector transformer winding produces a signal that triggers operation of the ground fault interrupt circuit, in response to the difference between currents produced by the current imbalance sensor transformer windings exceeding detected ground wire current by a prescribed value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.